The spine consists of vertebrae that are categorized into sections known as the cervical, thoracic and lumbar section in a flexible arranged column. The vertebrae are separated by small cartilaginous cushions known as intervertebral discs. Intervertebral discs are oblate spherical structures that maintain the space between adjacent vertebrae. Each intervertebral disc consists of an outer annulus fibrosus, which surrounds the inner nucleus pulposus. The annulus fibrosus consists of several layers of strong annular fibrocartilage to contain the nucleus pulposus and distribute pressure evenly across the disc wherein a mucoprotein gel serves to absorb shocks.
Deterioration of an intervertebral disc results in limited mobility and can cause severe pain. For instance, normal aging causes the nucleus pulposus to lose fluid and contract in volume resulting in a reduction in the intervertebral space. Any reduction of space between adjacent vertebrae may put pressure on the nerves of the spinal column. Further, a reduction in volume of the nucleus pulposus reduces the disc's ability to absorb shock which can result in disc herniation. The bulge of a herniated disc may also put pressure on nearby nerve structures resulting in pain as well as diminished range of motion.
Surgical options are available including laminectomy and discectomy combined with vertebral fusion and/or dynamic stabilization. However, these surgical options are highly invasive and require prolonged hospitalization and recovery. More recently, artificial disc replacement prosthetics have been used to replace or augment all or part of the removed or resected intervertebral disc.
In order to reduce the pain associated with the movement of the intervertebral joint, surgical intervention is often indicated as a means to alleviate pressure upon the spinal cord while concomitantly stabilizing the associated vertebrae. This involves a surgical procedure to distract the disc and or vertebra, or portions thereof, and the insertion of bone fusing material into the cavity of the opposing vertebra. Corpectomy devices have been developed to help support the spine and maintain the normal spacing between opposing vertebrae. Some of these devices may be packed with fusing material to ensure solid bone growth between the two vertebrae. Typically, corpectomy devices are manufactured at various heights requiring that a cavity between opposing vertebrae to be distracted to a dimension corresponding to the sized corpectomy device. The surgical procedure to prepare the implant site can be difficult and lengthy. Moreover, the procedure can increase risk of trauma to the tissues surrounding of the implant site.